<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .float{
      float: left;
    }
    #main{
      width: 100%;
      background-color: pink;
    }
    #main-wrap{
      margin: 0 150px 0 200px;
    }
    #left{
      width: 200px;
      /* 这里位移外层父亲的宽度的距离，这里的父亲就是body */
      margin-left: -100%;
      background-color: antiquewhite;      
    }
    #right{
      width: 150px;
      /* 向左边位移-150px */
      margin-left: -150px;
      background-color: aqua;
    }
    </style>
  </head>
  <body>
    <div id="main" class="float">
      <div id="main-wrap">main</div>
    </div>
    <div id="left" class="float">left</div>
    <div id="right" class="float">right</div>
  </body>
</html>
